Dokumentasi mengenai efektivitas kreatina dalam pengobatan penyakit-penyakit muskular, neuromuskular, dan neuro-degeneratif sudah anyakbanyak dilakukan<ref>Creatine and Creatine Kinase in Health and Disease (2007) Series: Subcellular Biochemistry , Vol. 46 Salomons, Gajja S.; Wyss, Markus (Eds.) 2007, XVIII, 352 p., Hardcover ISBN 978-1-4020-6485-2</ref> tapi kegunannya sebagai peningkat performa di dalam olah raga (sebagai suplemen olah raga) sering dipertanyakan<ref>{{cite web | author = Edward G. McFarland, M.D. | title= Sports Enhancers - The Good, the Questionable and the Dangerous |url= http://www.hopkinshospital.org/health_info/Mens_Health/Reading/sports_enhancers.html | publisher = Johns Hopkins Hospital | date=[[2002-10-04]] | accessdate=2008-01-08}}</ref>. Beberapa organisasi bahkan menyarankan agar penggunannya sebaiknya dilarang <ref> {{cite web |url=http://www.foodnavigator.com/news/ng.asp?id=40041-afssa-calls-for |title=AFSSA calls for creatine ban}}</ref> <ref> {{cite web |url=http://www.ncaa.org/wps/portal/home?WCM_GLOBAL_CONTEXT=/wps/wcm/connect/NCAA/Media+and+Events/Broadcasting/Broadcasting+Manual/Sect3/AdvStand |title=The NCAA's Advertising and Promotional Standards |date=2006-11-01}} "...impermissible Nutritional Supplements that NCAA member institutions may not provide to student-athletes (e.g., creatine..." </ref> <ref> {{cite web |url=http://www.irlgov.ie/debates-98/1dec98/sect2.htm |title=Parliament of Ireland}} See section titled "Ban on creatine". </ref> Despite this, creatine remains very popular.<ref> "Creatine sales totaled $193 million in 2003 — or roughly 10% of the $1.9-billion sports supplement market, according to the San Diego-based Nutrition Business Journal</ref>.
